Some neuromodulation devices have the ability to modulate their own stimulation settings quickly based on immediate feedback from target tissue (e.g. muscle) that they are stimulating, since the target tissue responds quickly to stimulation. For example, electromyography (EMG) can be used to record and evaluate the electrical activity of muscles, which provides information regarding the activation level and/or recruitment of the muscles. This information can be processed and used to modulate the neurostimulation parameters applied to the muscles, thereby improving the efficacy of the stimulation device.
Vagus nerve stimulation (VNS) for the treatment of chronic inflammatory diseases, on the other hand, is not easily programmed for optimal result, as decreases in inflammation take hours to days to manifest. Consequently, it would be desirable to identify alternative markers or surrogates that indicate activation of the cholinergic anti-inflammatory pathway by VNS. In addition, it would be desirable to use these alternative markers or surrogates to identify patients that may be suitable for receiving VNS therapy. Furthermore, it would be desirable to directly modulate these markers or surrogates as an alternative or supplemental way to treat inflammation.